The search for life on other planets has captivated mankind for decades.
But the reality could be a little less like the Hollywood blockbusters, scientists have revealed.
They say if there was life on the red planet, it probably will present itself as fossilized bacteria - and have proposed a new way to look for it.
Here are the most promising signs of life so far -
WaterWhen looking for life on Mars, experts agree that water is key.
Although the planet is now rocky and barren with water locked up in polar ice caps there could have been water in the past.
In 2000, scientists first spotted evidence for the existence of water on Mars.
The Nasa Mars Global Surveyor found gullies that could have been created by flowing water.
The debate is ongoing as to whether these recurring slope lineae (RSL) could have been formed from water flow.
MeteoritesEarth has been hit by 34 meteorites from Mars, three of which are believed to have the potential to carry evidence of past life on the planet, writes Space.com.
In 1996, experts found a meteorite in Antarctica known as ALH 84001 that contained fossilised
